| Current Conditions | ||
| Temp |  | 2.9 C |
| RH | | 18 % |
| Wind | | NNE 15 mph |
| Road | | Open (4x4) |
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Hawaiian Islands Synoptic Discussion and Guidance 519 FXHW60 PHFO 051625 CCA AFDHFO Area Forecast Discussion...CORRECTED National Weather Service Honolulu HI 625 AM HST Sun Jul 5 2020 .SYNOPSIS... Light to moderate east southeast winds will continue through tonight. Scattered showers will affect leeward and interior areas at this afternoon as sea breezes develop, but clouds and showers will favor windward areas otherwise. A more typical trade wind pattern will resume on Monday with winds strengthening Tuesday and maintaining through the end of the week. && .DISCUSSION... A 1031 mb high is centered around 1500 miles north of Honolulu this morning driving light to moderate east southeast winds across the state. The winds are lighter than usual due to a surface trough between 500 and 800 miles north of Honolulu and a deep low northwest of the state. An area of enhanced tropical moisture moving in with the wind flow will continue to impact the island chain through tonight. Radar and infrared satellite show low cloud cover with scattered showers across Kauai and the Big Island, particularly across the southeast sections of both islands, while mostly dry conditions persist over Maui County and Oahu this morning. Rainfall amounts overnight were generally light to moderate. The next area of clouds to the east and northeast of Hawaii will move in later today and tonight. By afternoon, clouds and showers are expected to build along island interiors and leeward sections of most islands due to incoming sea breeze. Expect light to moderate showers in these areas, shifting to windward areas tonight, with the main area of clouds and showers finally passing west of the island chain on Monday. Winds will maintain through tonight, then begin to strengthen Monday as the trough weakens and the high becomes the more dominant force. The incoming airmass is expected to be a bit drier and more stable, however, clouds and showers will focus over windward slopes as trades become breezy by Tuesday through the end of the week. Showers will occur mostly during the nighttime with the exception of the Kona slopes on the Big Island (afternoon showers). && .AVIATION... A light easterly trade wind flow will persist through today as a ridge of high pressure stays far north of the islands. The pool of warm and unstable air continues on its way out. In doing so, heavy showers moved into Kauai shortly before midnight. These showers are currently dissipating over interior Kauai. Showery weather is still happening over the Hilo and Puna districts of the Big Island this early Sunday morning. Scattered showers are also detected moving down the adjacent Kau coastal waters, briefly touching the shoreline at times. There is no AIRMET Sierra for this area, but will be monitored closely. As part of a drier and more stable air mass spreading in, these showers affecting windward Big Island are expected become isolated by mid morning. Lingering moisture and instability, coupled with local sea breeze and daytime heating, will lead to some isolated, spotty, showers over the lee and interior sections of the remaining islands this afternoon. Scattered showers are on tap for leeward Big Island this afternoon. Also, the trade winds, although weak, will be able to bring in a few showers onto the windward areas of all the islands. So do expect brief MVFR ceilings and vis with these showers. The amount of showers is expected to be less compared to Saturday. A more regular trade wind pattern should be in place by this evening. && .MARINE... Light to moderate east-southeast winds will hold today as a weak trough west of Kauai continues westward and away from the state. Winds will remain light enough for afternoon sea breezes to develop for some leeward coastal areas today. A return of a more typical trade wind pattern is anticipated Monday with winds hitting the moderate to fresh range, then the fresh to strong category by Tuesday. As a result, a Small Craft Advisory for winds will be possible as early as Tuesday for the typical windier waters from Maui County to the Big Island. For the extended, the advisory may need to be expanded to other marine areas as the trades continue to ramp up. Seas will approach, if not reach, the advisory level (10 ft) over the Alenuihaha Channel and waters south of the Big Island by the end of the week. Surf along south facing shores will remain small with mainly a mix of small south and south-southeast energy holding. Guidance does introduce a small background south-southwest swell arriving today, which will support the small surf continuing into Monday. Another south-southwest pulse will be possible Wednesday through the second half of the upcoming week. For the extended, guidance depicts a a solid area gales setting up in the Tasman Sea through the first half of the week, which could result in an uptick in surf locally by mid July. Surf along east facing shores will remain small through Tuesday, then gradually trend up through the rest of the week as the trades increase locally and upstream of the islands across the eastern Pacific. Surf along north facing shores will remain near the summertime average through the upcoming week. A background, medium period, northwest swell may be enough for small surf at select spots today. This will be short-lived and out by Monday. Some spots exposed to trade wind wrap may notch up through the second half of the upcoming week. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Foster AVIATION...H Lau MARINE...Gibbs Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office |
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